The cave meanders two miles below northern Alabama, with passageways that veer into mysterious dark areas, sediment deposits, a waterfall, and plunge pools. Ancient footprints are embedded in its most remote passage. The names of Civil War Union soldiers remain scrawled on a wall.
Leaning over because the ceiling was so low, Alan Cressler detached a light from his helmet on July 30, 1998 and raked the beam across the surface above him.
The artwork of a human being who lived centuries ago has appeared: possibly a bird, with a rounded head.
“Once I saw that, I was like ‘OK,'” Cressler, who now works for the United States Geological Survey, said in an interview this week. “It gives me chills today to talk about it. I just recognized the immediate importance of it.
With archaeologist, 3D photography expert and others, Mr. Cressler further explored the cave, known as the 19th Unnamed Cave, and its art over the years. This week, they published their findings in the journal Antiquity. The study highlighted the role of 3D technology in uncovering artwork that was not initially visible to Mr Cressler more than 20 years ago when he was pressed so close to the ceiling that he couldn’t see the full array that radiated in all directions above. him.
Jan Simek, an archaeologist at the University of Tennessee and co-author of the paper, said the rock art was one of the largest found in North America, deep within a convoluted dark zone where the natural light could not reach.
Using radiocarbon dating and analysis of pottery shards, researchers estimate that the art dates back to the Middle and Late Woodland periods, between 500 and 1000 AD, when farming, hunting and gathering gave way to food production and sedentary life in the region.
There are figures with human features, a coiled snake with a tail rattle and a forked tongue, and a 10-foot-long serpent snaking through the expanse. Some incorporate ceiling features into their design, such as the snake that appears to emerge from a natural crack.
Ghostly humanoid figures are adorned with trappings. Charred fragments of river cane suggest the artwork, finely incised in a mud veneer, could have been a team effort, with someone holding a torch while the artist or artists worked.
Early artists most likely lay on sediment deposits when making their mud sculptures, either with their fingers or with delicate toothed tools.
“It’s very detailed,” Dr. Simek said. “It covers an acre of ceiling area. The glyphs are in one chamber, but the cave continues.
Since rock art was first documented in North America in 1979, Dr. Simek and Mr. Cressler have been studying what is known as Dark Zone rock art, which involves exploring inaccessible passages in natural light.
The cave, documented in 1979 in Tennessee, contained mud drawings, 750 to 800 years old, depicting pre-Columbian Native American religious themes, according to the Antiquity Study. Since then, 89 other pre-Columbian rock art sites have been identified in southeastern North America. The oldest is almost 7,000 years old, but most of them date from 800 to 1600 AD.
Some are on private property and these finds are kept secret to protect the area from vandals. Others are on public land, including in Virginia, Tennessee, Kentucky and Alabama. Some can only be reached by boat as the rivers have risen to entrances that were once accessible by land.
The use of 3D modeling in Alabama’s unnamed 19th cave “promises a new era of ancient rock art discovery” as it reveals images that otherwise could not be perceived, the researchers said in their study.
The technique has been used elsewhere, for example to create a replica of the art in the Lascaux caves in France, but not so much to search, as Dr Simek put it, “to see if there are things that we cannot see”.
The researchers used a technique called photogrammetry, in which a camera slowly moves along a track, taking overlapping images which are then stitched together using software. This creates a seamless representation that showcases even the most beautiful mud carvings, said Stephen Alvarez, founder of the Ancient Art Archive and co-author of the study. He was responsible for the 3-D work in the 19th unnamed cave.
Over 16,000 stacked photographs produced the map of known cave art.
“It’s like magic,” Mr. Alvarez said. “Here is this thing that had been invisible for over 1,000 years and suddenly came to life. Even though people have been abducted, their stories are still there.
The method is useful because the uneven features of a cave ceiling can cast shadows that obscure the delicate lines of the art. Mr. Cressler said these features complicated his early attempts to document the work with a camera.
Dr Simek said the use of photogrammetry was even more intriguing because ancient artists had no such technology, or ability, to see the big picture. Unlike the rock art, which is out in the open, the artists inside the cave chamber could not stand back and think about their work in progress from a distance.
“The creators of these images couldn’t see them in their entirety except in their minds,” he said. “It means they had an idea of what to draw and move around while they were doing it.”
But exactly what the artists had in mind has so far eluded researchers.
Dr. Simek said the project’s work with Native American collaborators helped interpret the cave’s possible relationship to the supernatural.
Dustin Mater, a Chickasaw citizen and artist who works with Mr. Alvarez’s archive, said the rock art’s themes and imagery were similar to those he learned from tales of tribal elders, such only cave portals to the underworld and a winged human figure. armed with a mace.
“It’s almost speculative, but there are nuances today that run through our traditions and our stories,” said Mr Mater, whose ancestors were among the indigenous people forcibly evicted from the northwest of Alabama in the 1800s. “Living cultures take symbols, then revive them and give them meaning.”